Cyber-pseudepigraphy: A New Challenge for Higher Education Policy and Management

There is no lack of critical literature dealing with cyber-plagiarism and the implications for assessment in higher education. The practice of the selling of academic papers through the Internet is generally included under the category of plagiarism, although it is suggested that this ought to be considered under the separate category of cyber-pseudepigraphy. Pseudepigraphy is defined in this essay as the deliberate ascription of false authorship to a piece of writing, and cyber-pseudepigraphy is defined as using the Internet to have another person write an academic essay or paper, without this authorship being acknowledged. It is suggested that cyber-pseudepigraphy has widespread implications, and five critical issues are discussed. The essay finally raises the prospect of a return to some form of unseen examination as a method of student assessment as a way of dealing with this problem

Byzantine Stochastic Gradient Descent

This paper studies the problem of distributed stochastic optimization in an adversarial setting where, out of the $m$ machines which allegedly compute stochastic gradients every iteration, an $\alpha$-fraction are Byzantine, and can behave arbitrarily and adversarially. Our main result is a variant of stochastic gradient descent (SGD) which finds $\varepsilon$-approximate minimizers of convex functions in $T = \tilde{O}\big( \frac{1}{\varepsilon^2 m} + \frac{\alpha^2}{\varepsilon^2} \big)$ iterations. In contrast, traditional mini-batch SGD needs $T = O\big( \frac{1}{\varepsilon^2 m} \big)$ iterations, but cannot tolerate Byzantine failures. Further, we provide a lower bound showing that, up to logarithmic factors, our algorithm is information-theoretically optimal both in terms of sampling complexity and time complexity

UV-induced modification of stress distribution in optical fibers and its contribution to Bragg grating birefringence

This paper discusses the importance of stress-induced contributions to the photo-induced birefringence observed in fiber Bragg gratings. Optical tomography measurements are performed in exposed and unexposed fibers to extract the stress profiles induced by UV-writing of fiber Bragg gratings for various exposure levels. A photoelastic analysis and a high-order isoparametric finite elements method are then used to calculate the birefringence caused by stress profile modifications. The results are compared to the birefringence directly measured by spectral analysis of a chirped fiber grating with multiple phase-shifts. We can therefore estimate the fraction of the photo-induced birefringence due to stress-induced anisotropy following UV exposure. © 2008 Optical Society of America

Clear Experimental Signature of Charge-Orbital density wave in Nd1−x_{1-x}Ca1+x_{1+x}MnO4_{4}

Single Crystals of Nd$_{1-x}$Ca$_{1+x}$MnO$_{4}$ have been prepared by the travelling floating-zone method, and possible evidence of a charge -orbital density wave in this material presented earlier [PRB68,092405 (2003)] using High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In the current note we present direct evidence of charge-orbital ordering in this material using heat capacity measurements. Our heat capacity measurements indicate a clear transition consistent with prior observation. We find two main transitions, one at temperature $T_{_H}=310-314$ K, and other at $T_{_A}=143$ K. In addition, we may also conclude that there is a strong electron-phonon coupling in this material.Comment: 7 pages, 8 figure